JPS6248608B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to improvements in rear suspensions for automobiles.

(Prior Art) A system called a trailing arm type or a semi-trailing arm type has been known as an independent rear suspension for automobiles.
This rear suspension system has a trailing arm that extends in the longitudinal direction of the vehicle body and whose front end is attached to the vehicle body so that it can swing vertically.The rear end of this trailing arm has a hub support for supporting the wheel hub. The member is fixed. Further, a damper is arranged between the rear end of the trailing arm and the vehicle body above it. This type of rear suspension has a simple structure and is lightweight, but in order to sufficiently increase the lateral rigidity of the trailing arm, its cross-sectional shape must be made large and the attachment points to the vehicle body must be This requires a wide lateral spacing between the two, which increases the size of the trailing arm, which is disadvantageous in terms of weight.

A structure that solves these problems was developed in 1983.
Proposed by No. 62205. In this proposed structure, the front end of the trailing arm extending in the longitudinal direction of the vehicle body is swingably attached to the vehicle body, and the wheel hub is supported at the rear end. The outer ends of the two arranged lateral links are rotatably connected, and the inner ends of the lateral links are rotatably connected to the vehicle body. This type of rear suspension is advantageous in that the rigidity of the trailing arm does not need to be very high, but if the wheels move vertically relative to the vehicle body, they will Even when the vehicle moves toward the vehicle or rebounds, the wheels tend to move in the toe-out direction, resulting in unstable steering such as oversteer while driving on a curved road. On the other hand, in West German Published Patent Application No. 2038880, a triangular upper arm disposed above and two lower arms arranged in parallel at the front and back disposed below are used to control the wheels. A configuration that supports this is disclosed. In this case, the attitude of the wheel is basically regulated by these three arms, so by selecting the position, arrangement, and length relationship of these arms, Even when the wheels move in the vertical direction relative to the vehicle body, the toe of the wheels can be set appropriately, and compared to the structure of the prior art described above, driving stability due to toe changes can be improved. It is. However, the upper arm of this publication is constituted by a triangular arm having two pivot points to the vehicle body spaced apart in the longitudinal direction, and is therefore disadvantageous both in terms of space and riding comfort. In other words, it is necessary to secure a large space in order to allow the triangular upper arm to swing as the wheel moves up and down. Generally, the space behind the wheels is very limited due to the need to install other suspension components such as stabilizers, so the swinging space of the triangular arm is limited to avoid interference with other parts. Many restrictions must be met in order to ensure
Design freedom is considerably restricted. Furthermore, while driving, impact loads are applied to the wheels in the front and rear directions due to the undulations of the road surface. As a result, the shock is easily transmitted to the vehicle body, worsening the ride comfort. It is possible to alleviate this impact by making the elastic bushing of the two-point pivot joint softer, but if it is made too soft, the camber of the wheel will be affected when lateral force is applied to the wheel during rotation. The change (in the positive direction) becomes large, resulting in a decrease in grip strength and poor steering stability.

Also, the rear end of the trailing arm in this publication is
For wheel support members that rotatably support wheels,
They are connected so that they can rotate freely. Then,
In order to enable smooth vertical movement of the wheel, it is essential that the circumferential motion of this part be smooth, and in order to ensure reliability, it is actually necessary to separately install parts such as large seal boots. As a result, there is a concern that the structure will become more complex.

(Objective of the present invention) An object of the present invention is to suppress the tendency to toe out due to vertical movement of a wheel in a rear suspension having a swing arm extending in the longitudinal direction of the vehicle body and a lateral link extending in the lateral direction. In addition to providing a lightweight and compact suspension that does not impair riding comfort, it also allows for appropriate toe angle changes in response to lateral forces applied to the wheels during turning. To provide a rear suspension for an automobile that can further improve running stability.

(Configuration of the present invention) In order to achieve the above object, the present invention is configured as follows. That is, the present invention extends in the longitudinal direction of the vehicle body, has one end attached to the vehicle body so as to be swingable in the vertical direction, supports a wheel support member at the other end, and applies a force in the longitudinal direction and a rotational force in the wheel rotation direction to the wheel support member. The swing arm is configured to be capable of transmission, and three lateral links extend in the lateral direction of the vehicle body independently of each other, one end of each lateral link is connected to the wheel support member, and the other end is connected to the vehicle body. The wheel support member is connected to the vehicle body via the swing arm so as to allow lateral displacement relative to the vehicle body, and the wheel support member of one lateral link The attachment point is arranged above the attachment point of the other two lateral links, and the attachment point of the two lateral links connects the attachment point of the one lateral link and the point of application of lateral force to the wheel. An attachment point of a lateral link that is arranged in front and behind a narrow straight line, and that the distance between the attachment point of the lateral link placed on the front side of the two lateral links to the wheel support member and the straight line is on the rear side. and the straight line. In a preferred aspect of the present invention, the attachment point of the upper lateral link to the wheel support member is above and in front of the wheel center, and the attachment point of the lower front lateral link is below and above the wheel center. At the front, attachment points of the lateral links arranged on the lower rear side are arranged below and behind the wheel center, respectively.

According to this configuration of the present invention, the attitude of the wheel support member, and therefore the wheel, is regulated only by the three lateral links, and the arrangement of the three lateral links, that is, the position of each lateral link. By appropriately determining the inclination angle and length in the vertical and longitudinal directions, the mounting position to the wheel support member, and the lateral rigidity at the mounting position, it is possible to prevent lateral forces and longitudinal forces on the wheel during bumps, rebounds, etc. It becomes possible to control the toe change and camber angle change of the wheel in a desired manner when a force is applied. In the present invention, one of the three lateral links is attached to the wheel support member above the other two, and the other two are attached below.
Since the lateral links are located at the front and rear of the wheel center, toe changes when the wheel bumps or rebounds, or when lateral forces are applied to the wheel, are controlled by these two lower lateral links. It turns out.

The swing arm only needs to have the strength and rigidity to transmit the force in the longitudinal direction of the vehicle body and the rotational force in the wheel rotation direction, and it is necessary that it does not restrict the wheel attitude control by the three lateral links. be. To achieve this, it is necessary to reduce the lateral rigidity of the swing arm so that it can flex laterally during bumps, rebounds, etc., or to attach the swing arm so that it can be displaced laterally relative to the vehicle body, or to The swing arm may be configured to allow lateral displacement of the wheel support member, such as by coupling the arm and the wheel support member such that relative displacement is possible.

(Effects of the Invention) According to the present invention, three lateral links extending in the lateral direction of the vehicle body are provided, and one of the lateral links is positioned higher than the other two at the attachment point to the vehicle body support member. The two lower lateral links are located at is shorter than the distance between the rear attachment point and the straight line. Therefore, if lateral force acts on the wheel during rolling,
The reaction force of the front link increases, and as a result, the amount of deformation of the bush etc. on the front side becomes larger than that on the rear side, causing the front side to be displaced inward to a relatively large extent. That is, the wheels tend to slightly toe-in. Therefore, running stability can be improved. Note that since the three lateral links are arranged at regular intervals, the reaction force of the lateral force can be dispersed and supported, which is advantageous in ensuring rigidity against the lateral force.

(Description of Embodiments) Referring to FIGS. 1 to 5, a wheel 10 is rotatably supported by a wheel support member 12 and connected to a vehicle body 16 via a suspension device 14. The suspension device 14 includes a swing arm 18, a first lateral link 20, a second lateral link 22, a third lateral link 24, and a shock absorber 26. The swing arm 18 has a vertically wide plate shape and extends in the longitudinal direction of the vehicle body, and its front end is attached to a bracket provided on the vehicle main frame 28 by a rubber bushing fixed to the swing arm 18 and a bolt 38 passing through the rubber bushing in the lateral direction of the vehicle body. The rear end is attached to the wheel support member 12 with bolts 3.
It is fixed at 0. 1st lateral link 2
0 extends substantially transversely to the vehicle body, and one end is attached to the wheel support member 12 via a rubber bushing 20a so as to be rotatable around a horizontal axis in the longitudinal direction of the vehicle body, and the other end is attached to the vehicle body main frame 28 in a similar manner to the vehicle body main frame 28. It is attached via a rubber bushing so that it can rotate around a horizontal axis in the front-rear direction. One end of the second lateral link 22 and the third lateral link 24 is rotatably attached to the wheel support member 12 via rubber bushings 22a and 24a, respectively, about a horizontal axis in the longitudinal direction of the vehicle body, and the rubber bushings 22b,
24b to the rear subframe 32 on the vehicle body side so as to be rotatable about a horizontal axis extending substantially in the longitudinal direction of the vehicle body. Shock absorber 26
is equipped with a coil spring 34 and a damper 36,
Extending in the vertical direction, the lower end is rotatably attached to the wheel support member 12, and the upper end is rotatably attached to the vehicle body 16. Referring to FIG. 5, the mounting positions of the respective lateral links 20, 22, 24 on the wheel support member 12 are such that the second lateral link 22 is above and behind the wheel center 40, and the first lateral link 20 is above and behind the wheel center 40, and the second lateral link 22 is above and behind the wheel center 40. The three lateral links 24 are respectively attached to the wheel support member 12 at the front and rear positions below the wheel center 40. and,
The first
Attachment point of the lateral link 20, that is, the bush 2
The distance l ₁ between the center of 0a and the straight line L is shorter than the distance l ₂ between the attachment point of the third lateral link 24, that is, the center of the bush 24a and the straight line L.

When the wheel 10 receives a force in the vertical direction, the wheel 10 is displaced in the vertical direction, and the swing arm 1
8 is a bolt 38 for attaching the front end to the vehicle body
sway around. Therefore, the wheel center 40
is displaced along an arcuate trajectory centered on the bolt 38 at the front end of the swing arm 18.
In this case, since the wheel support member 12 is laterally supported by the three lateral links 20, 22, and 24, the lateral links 20, 22, and 24 also swing in the vertical direction, and their outer ends swing. Displaces laterally with movement. In the lateral link arrangement as in the illustrated embodiment, the first lateral link 20 is slanted laterally outwardly and slightly rearwardly and downwardly;
Its length is the shortest among the three lateral links. The second lateral link 22 is laterally outwardly inclined slightly forward and upwardly, and the third lateral link 24 is laterally outwardly inclined slightly downwardly. With this arrangement, for example, if the wheel is displaced upward, the outer end of the first lateral link 20 will be slightly displaced outward, but since the link 20 has a rearward inclination, it will not move outward. The amount of displacement is small. The outer end of the second lateral link 22 is displaced inward as the wheel is displaced upward. Further, the outer end of the third lateral link 24 is displaced outward, and the amount of displacement is equal to that of the first lateral link 24.
is larger than the amount of displacement at the outer end of. The outer ends of the first and second lateral links 20 and 22 are connected to the third
Since it is located forward of the outer end of the lateral link 24, a slight toe-in tendency occurs as a whole, and the camber angle decreases. Downward displacement or rehounding of the wheel results in a slight toe-out and a slight increase in camber angle. That is, when the wheel is displaced in the vertical direction, a toe angle displacement occurs as shown by curve a in FIG. 6, and a camber angle change has a similar tendency. Curve b in Figure 6 shows the toe angle change in the suspension of Utility Model Application No. 56-62205. From this figure,
The excellent toe angle control effect in this example is recognized. Along with this change in wheel posture,
The rubber bushing that attaches the swing arm 18 to the main body frame 28 undergoes an axial deflection, thus causing the swing arm 18 to undergo the required amount of lateral displacement.

Furthermore, when a lateral force is applied to the wheel such as when traveling on a curve, the attachment point of the first lateral link 20 is l ₁ and The attachment points of the three lateral links are separated by _l2 , and there is a relationship of _l2 > _l1 between them. Therefore, the reaction force generated on the first lateral link 20 is greater than the reaction force generated on the third lateral link 24, and the amount of lateral displacement caused by deformation of the bushing is also greater than the reaction force generated on the third lateral link 24. It is more likely that it will occur in Therefore, the wheel 10 causes a slight toe-in change due to the difference in displacement between the links 20 and 24.

Furthermore, with this arrangement, almost no toe angle change occurs with respect to longitudinal force.

FIG. 7 shows another embodiment of the present invention, in which the same parts as in the previous example are denoted by the same reference numerals. In this example, there are three lateral links 20, 2.
2 and 24 have been changed. Referring to FIG. 7, each lateral link 20, 22, 24
The mounting position on the wheel support member 12 is not in a straight line in the vertical plane in the longitudinal direction of the vehicle body, and the first lateral link 20 is attached to the axle shaft 40.
The second lateral link 22 is located above and in front of the axle 40, and the third lateral link 24 is located above and in front of the axle 40.
They are respectively installed below and at the rear of the vehicle. Even with this arrangement, the operation is similar to that of the previous example. In addition, as shown in the example, one lateral link is placed above the center of the wheel.
It is advantageous to arrange the other two links below the center of the wheel and in the front and back, since the axial forces of the lateral links can be approximately equalized.

The present invention is not limited to the arrangement of the embodiments described above, and the arrangement of the lateral link, the position of the attachment point to the wheel support member, and the rigidity may be varied in a range that does not adversely affect the axial force of the lateral link. Accordingly, it is possible to make the camber angle change and toe angle change of the wheel a desirable trend.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an embodiment of the suspension of the present invention, FIG. 2 is a rear view of the embodiment of the suspension of the present invention, FIG. 3 is a perspective view thereof, and FIG. 4 is a first embodiment of the suspension of the present invention.
Figure 5 is a side view, Figure 6 is a diagram showing changes in toe angle when the wheel is subjected to vertical force, Figure 7 is a side view of the suspension of another embodiment. It is a diagram. Explanation of symbols, 10... Wheel, 12... Wheel support member, 14... Suspension device, 18... Swing arm, 20... First lateral link, 22... Second
Lateral link, 24...Third lateral link, 2
6...Shock absorber, 28...Vehicle main frame.

Claims (1)

[Claims] 1. Extends in the longitudinal direction of the vehicle body, has one end attached to the vehicle body so as to be swingable in the vertical direction, supports a wheel support member at the other end, and acts on the wheel support member in the longitudinal direction and rotation in the wheel rotation direction. A swing arm configured to be able to transmit force, and three lateral links extending in the lateral direction of the vehicle body independently of each other, one end of each lateral link being pivotally connected to the wheel support member, and the other end being pivotally connected to the vehicle body. The wheel support member is rotatably mounted via means, and the wheel support member is connected to the vehicle body via the swing arm so as to allow lateral displacement relative to the vehicle body, and the wheel support member of one lateral link The attachment point on the member is arranged above the attachment point of the other two lateral links, and the attachment point of the other two lateral links is located at a distance between the attachment point of the one lateral link and the lateral force applied to the wheel. The laterals are arranged in front and behind a straight line connecting the points, and the distance between the attachment point of the lateral link to the wheel support member, which is located on the front side of the two lateral links, and the straight line is on the rear side. A rear suspension for an automobile, characterized in that the distance between the attachment point of the link to the wheel support member and the straight line is shorter than the distance. 2. The attachment point of the lateral link placed above to the wheel support member is above and in front of the wheel center, and the attachment point of the lateral link placed on the front side of the other two lateral links is located above and in front of the wheel center. The rear suspension for an automobile according to item 1 above, wherein the wheel-side attachment points of the lateral links arranged below and in front of the wheel center and on the rear side are respectively arranged below and behind the wheel center. .